What I know is that I need a powerful graphics card and CPU, and for the most part, not much else, as games dont require a ton of RAM, Hard Drive space, etc. What I don't know is what constitutes a "powerful" graphics card and CPU.

Basically what I need is for someone to explain what the different specs of computer components (mostly CPU, graphics card, and motherboard) mean, and which ones are important to a good gaming computer.

Also, on a similar note, I am not sure how to choose a power supply that will support all the components that I ultimately buy. Is there a tool out there that I can use for this?

This is not:

A specific "What hardware model should I buy?" buying recommendation.

Too localized. There are plenty of people who run into the same issues and don't know where to start.

Not constructive. I know we as a community can write great CW answers that are not "Buy a GeForce 12345 WhatEver™"

This is absolutely the kind of question we encourage. This is the exact opposite of the ones we close all the time.

Help people to help themselves. How do I find out what a good graphics card is? Which hardware is worth spending money on in a gaming rig? What kind of power supply do I need?

I know we have similar questions already, at least close it as a duplicate of those, not as off-topic. This is sending the wrong message.

Which should be a good jump start on what to look for and what to keep in mind about constructing a new machine for whatever purpose. In this case, eating Cheetos and drinking Fanta for eight hours straight.